Relay control circuit arrangement



Oct. 11, 1960 N. KIRCHNER 2,956,206

RELAY CONTROL CIRCUIT ARRANGEMENT Filed May 15, 1958 NVENTOR NORBEHT KIRGHNE R United- States PatentO 2,956,206 RELAY CONTROL CIRCUIT ARRANGEMENT Norbert Kirchner, Hamburg-Altona, Germany, assignor to North American Philips Company, Inc., New York, N.Y., a corporation of Delaware The present invention relates to a relay control circuit arrangement.

In relay tubes which are controlled by very highresistance voltage supplies, difiiculties can occur which do not permit the igniting of thetube with certainty. This prevents the reliable operationof a load, such as, for example, a relay connected in the circuit of the relay tube. voltages and negative auxiliary anode voltages it cannot always be ensured that the ignition passes with certainty from the auxiliary anode discharge path to the anode path, since the requirement that the auxiliary anode current flow with a predetermined minimum value for a predetermined minimum time is not always satisfied. Especially in control voltage supplies having a high internal resistance, the necessary minimum current cannot always be supplied so that before the ignition of the auxiliary anode discharge path a capacitor must be charged which is connected between the cathode and the auxiliary anode. This capacitor discharges and supplies the required current after the ignition. The relay tube can only be ignited in any positive half-period of the anode voltage if the current supplied by the control voltage supply is sufficient to charge the capacitor to the ignition voltage of the auxiliary path between two instants of ignition.

In most cases in which such an arrangement is employed it is required that in accordance with the current of the control voltage supply the relay tube either passes current during each positive half-period of the voltage at the anode or remains completely extinguished.

However, from the above it follows that when the current of the control voltage supply slowly decreases or increases, which may be due, for example, to a variation in the irradiation of a photo-electric cell, there is a region in which the control current charges the capacitor to the ignition voltage of the auxiliary path only after a few positive half-periods of the voltage at the anode. Consequently, the relay tube will ignite unevenly so that a relay operated by the tube will chatter.

The invention avoids this disadvantage in circuit arrangements for relay tubes which are fed with alternating voltage and are controlled by an integrated control voltage which depends upon high-resistance voltage supplies. In accordance with the invention, the working resistance of the relay tube is bridged by a capacitor and forms part of a resistance connected in the cathode lead of the relay tube. By this measure a region of uneven ignition of the relay tube is avoided in a simple manner.

In order that the invention may be readily carried into effect, it will now be described, by way of example, with reference to the accompanying drawing, in which:

Fig. 1 is a schematic diagram of an embodiment of the relay control circuit arrangement of the present invention; and

Fig. 2 is a voltage diagram illustrating the operation of the circuit arrangement of Fig. 1.

The essential feature of the circuit arrangement of Particularly in tubes which use positive anode ice Fig. 1 is the connection of a relay 1 and its smoothing capacitor 2 in the cathode lead of a relay tube-4 which is fed with alternating voltage through a transformer 3. This connection eliminates the uneven ignition of the relay tube. 1

- "As soon as an auxiliary anode 5 has first reached its ignition voltage with increasing irradiation of a photoelectric cell 6, the relay tube 4 ignites. Due to the voltage drop across a resistance 7 and the relay 1 the potential at the cathode 9 rises. After the relay tube 4 is extinguished, the cathode9 still is at a positive potential which decreases slowly only dueto the large time con stant of the relay 1 and the capacitor 2. When the next positive half-period of the voltage at the anode 8 occurs, the cathode 9 is still positive so that the potential difference AV (Fig. 2) between the cathode 9 and the auxiliary anode 5, which potential difference is necessary to ignite the auxiliary anode path 5, is reached even when a less negative potential is set up at the auxiliary anode 5. Thus, the relay tube 4 can again ignite though the photocell current has not yet lowered the auxiliary anode potential to the initial potential required for ignition. The capacitor 10 serves to integrate the voltage supplied by the photo-electric cell 6 so that the control voltage together with the ignition voltage taken from a transformer winding 11 is always sufiicicnt to ignite the relay tube 4 with certainty. A resistance 12 is required in order to prevent the relay tube 4 from being ignited due .to the capacitor 10 being slowly charged when the photo-electric cell is not irradiated or irradiated weakly only.

In the voltage diagram of Fig. 2, reference letter A designates the variable anode potential, K the cathode potential and H the auxiliary anode potential of a relay tube fed with alternating voltage as a function of time.

When the illumination of the photo-electrc cell decreases, the same operation occurs in reverse order so that, when the irradiation'falls below a predetermined level, the relay tube 4 remains extinguished and does not pass through a region of uneven ignition. The relay control circuit arrangement ofthe present invention can be used to particular advantage in flame-guarding devices and twilight switches which require reliable and correct switching.

While the invention has been described by means of a specific example and in a specific embodiment, I do not wish to be limited thereto, for obvious modifications will occur to those skilled in the art without departing from the spirit and scope of the invention.

What is claimed is:

1. A relay control circuit arrangement comprising an electric discharge tube having an anode, a cathode and an auxiliary anode, means for applying an alternating supply voltage to said anodes and cathode, a relay winding connected to said cathode and in common with said auxiliary anode and said anode, means producing a control voltage, means for applying said control voltage to said auxiliary anode to control the ignition of said tube, and reactance means connected to said cathode and in common with said auxiliary anode and said anode for slowing the rate of change of the cathode voltage relative to that of said auxiliary anode upon change in the magnitude of said control voltage.

2. A relay control circuit arrangement comprising an electric discharge tube having an anode, a cathode and an auxiliary anode, means for applying an alternating supply voltage to said anodes and cathode, a relay winding connected to said cathode and in common with said auxiliary anode and said anode, means producing a control voltage, means for applying said control voltage to said auxiliary anode to control the ignition of said tube, and capacitive reactance means connected to said cathode and in common with said auxiliary anode and said anode for slowing the rate of change of the cathode voltage relative to that of said auxiliary anode upon change in the magnitude of said control voltage.

3. A relay control circuit arrangement comprising an electric discharge tube having an anode, a cathode and an auxiliary anode, means for applying an alternating supply voltage to said anodes and cathode, a relay wind.- ing connected to said cathode and in common with said auxiliary anode and said anode, means producing a control voltage, means for integrating said control voltage with the alternating voltage applied to said auxiliary anode thereby to produce an integrated control voltage, means for applying said integrated control voltage to said auxiliary anode to control the ignition of said tube, and a capacitor connected in parallel circuit arrangement with said relay winding, said parallel circuit arrangement having a substantially large time constant thereby slowing the rate of change of the cathode voltage relative to that of said auxiliary anode upon change in the magnitude of said control voltage.

4. A relay control circuit arrangement comprising an electric discharge tube having an anode, a cathode and an auxiliary anode, means for applying an alternating supply voltage to said anodes and cathode, a relay Winding connected to said cathode and in common with said auxiliary anode and said anode, means producing a variable substantially direct control voltage, said control voltage producing means comprising a photosensitive cell coupled between said auxiliary anode and said alternating supply voltage applying means, means for superposing said control voltage on the alternating voltage applied to said auxiliary anode thereby to produce an integrated control voltage, means for applying said integrated control voltage to said auxiliary anode to control the ignition of said tube, and capacitive reactance means connected to said cathode and in common with said auxiliary anode and said anode for slowing the rate of change of the cathode voltage relative to that of said auxiliary anode upon change in the magnitude of said control voltage.

5. A relay control circuit arrangement comprising an electric discharge tube having an anode, a cathode and an auxiliary anode, means for applying an alternating supply voltage to said anodes and cathode, a relay winding connected to said cathode and in common with said 45 auxiliary anode and said anode, means producing a variable substantially direct control voltage, said control voltage producing means comprising a photosensitive cell coupled between said auxiliary anode and said alternating supply voltage applying means, means for superposing said control voltage on the alternating voltage applied to said auxiliary anode thereby to produce "an integrated control voltage, means for applying said integrated control voltage to said auxiliary anode to control the ignition of said tube, and a capacitor connected in parallel circuit arrangement with said relay winding, said parallel circuit arrangement having a substantially large time con stant thereby slowing the rate of change of the cathode voltage relative to that of said auxiliary anode upon change in the magnitude of said control voltage.

6. A relay controlcircuit arrangement comprising an electric discharge tube having an anode, a cathode and an auxiliary anode, means for applying an alternating supply voltage to said anodes and cathode, said alternating supply voltage applying means comprising a transformer having a primary winding and a plurality of secondary winding portions connected in series with each other, a relay winding connected to said cathode and in common with said anode through a. first of said winding portions and with said auxiliary anode through a second of said winding portions, means producing a substantially direct control voltage, said control voltage producing means comprising a photosensitive cell, means coupling said cell across a third of said winding portions, means for superposing said control voltage on the alternating voltage applied to said auxiliary anode thereby to produce an integrated control voltage, said integrated voltage producing means comprising a resistance-capacitance circuit included in said cell coupling means and interposed between the said cell and a common point between said second and third winding portions, means for applying said integrated control voltage to said auxiliary anode to control the ignition of said tube, and a capacitor connected in parallel circuit arrangement with said relay winding, said parallel circuit arrangement having a substantially large time constant thereby slowing the rate of change of the cathode voltage relative to that of said auxiliary anode upon change in the magnitude of said control voltage.

References Cited in the file of this patent UNITED STATES PATENTS 1,832,707 Hull NOV. 17, 1931 2,125,073 Knowles July 26, 1938 2,838,716 Spierer June 10, 1958 

